# Haar space

> English word · Noun

## Definitions
1. A finite-dimensional subspace V of 𝒞(X, 𝕂), where X is a compact space and 𝕂 either the real numbers or the complex numbers, such that for any given f∈𝒞(X, 𝕂) there is exactly one element of V that approximates f "best", i.e. with minimum distance to f in supremum norm.

## Etymology
Named after Hungarian mathematician Alfréd Haar.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/haar-space